Photogrammetry extracts data from two-dimensional images and maps them into a three-dimensional space, reconstructing the object being imaged. Put another way, photogrammetry is the technique of obtaining precise geometrical measurements and three-dimensional data of an object from two or more two-dimensional photographs of that object. Photogrammatic processing is based on the principle of triangulation, whereby intersecting lines in space are used to compute the location of a point in all three dimensions. Long-range photogrammetry was first used to survey buildings in 1849 and over the course of the latter part of the 19th century, evolved into aerial photogrammetry by the early 1900's. Aerial photogrammetry, which typically refers to oblique or vertical images acquired from distances that are greater than 300 meters, is used to measure the geometry of objects in specializations such as forestry, archeology, cartography, geology and urban planning. Close-range photogrammetry, which has an object-to-camera distance of less than 300 meters, has been used in manufacturing, the analysis of ancient artifacts, traffic accidents and in plastic surgery applications.
Optical projection, reflection or scattering is a process whereby a form of electromagnetic radiation, such as visible light, infrared light, or gamma rays, is forced to deviate from a rectilinear trajectory to an alternate trajectory by one or more non-uniformities within the medium through which they pass or from non-uniformities on a surface from which they reflect and/or scatter from a surface. In the past, optical projection has been used in combination with photogrammetry, but only in the limited role of placing optical targets onto an object which is to be measured. This is a substantially different role than the one disclosed herein. Hence, there is a strong need to develop a system which is capable of determining the location of a module or surface geometry of a part by using photogrammetry to determine the locations in space of optical beams themselves as they are projected from a module or reflect from a part which does not require physical contact or visualization of the module or part.